A typical mobile communication network, for example a wide area network, comprises base stations and user equipments, as well as access points, like femto access points. In particular, such a mobile communication network may be a UMTS, a 3GPP Long-Term-Evolution (LTE) or 3GPP Long-Term-Evolution-Advanced network (LTE-A). The base stations may be a NodeB (NB) or enhanced NodeB (eNodeB, eNB) User equipments may be handed over from base stations to femto access points like Home eNode Bs (HeNBs).
For the handover, a PCI (physical cell ID) algorithm may be used, wherein a PCI value is assigned to each base station or femto access point. In traditional wide area networks, a centralized PCI selection algorithm relies on the OAM (operation and maintenance) to provide a single PCI value that is not in collision with any of its neighbors. For a network planned macro deployment, this is possible to achieve, based on careful design (centralized planning of PCIs). However in an uncoordinated, heterogeneous network deployment with HeNBs or pico cells this is difficult to achieve. HeNBs are deployed in an ad-hoc manner. Exact location is impossible to determine in many cases. Even if the HeNBs report detailed radio measurements to OAM, such radio measurements can change very quickly. The HeNB itself may be moved. Therefore PCI assignment can never eliminate collisions in uncoordinated, heterogeneous networks.
There may be a need for providing a reliable and computational inexpensive method for handing over a user equipment connected to a base station from the base station to a femto access point.